The diffusivity and solubility of deuterium in a high chromium martensitic steel

The permeability, diffusivity and solubility of deuterium in the martensitic stainless steel MANET II have been studied in the temperature range 194-465 C by applying a time dependent gas-phase permeation technique. It was found that the temperature dependence of diffusivity and solubility could not be described by a simple Arrhenius expression over the entire temperature range investigated. At lower temperatures (below about 330 C) the diffusivity was found to be greatly reduced by the effects of trapping. Oriani's model has been applied to obtain the trapping energy and number density of the traps as well as the relative amounts of deuterium dissolved at lattice and trap sites. It is suggested that the most likely sites for trapping are at interfaces between the martensitic laths and between second phase particles and the surrounding metal matrix. (orig.)